The Gasoline Particulate Filter (GPF) technology has been derived from successful experience with Diesel Particulate Filters and is available. It ensures control of ultrafine particles from Gasoline Direct Injection (GDI) engines under real-world driving conditions.
GDI is a key technology of gasoline engine development to reduce CO2 emissions while improving torque and power output. However the drawback of GDI engines is an increase in Particle Number (PN) emissions compared to conventional Port Fuel Injection (PFI) engines.
Latest GDI vehicles can achieve the PN limit of 6×1011/km on the regulatory test cycle (NEDC or WLTC) but the RDE test procedure however also includes particle counting in a wide range of engine map operation.
As of September 2017 a Not-To-Exceed (NTE) emissions limit is set for Real-Driving Emissions (RDE) of new car models with a Conformity Factor (i.e. NTE/Euro 6 limit ratio) of 1.5 (1.0 + error margin of 0.5 to be reviewed) for the number of particles. It has applied to all new cars since September 2018. To meet that challenge, the Gasoline Particulate Filter (GPF) has been developed for GDI cars and has been introduced to the market with the entry into force of RDE requirements for PN.